Preserve inline YAML document starts in aggregate reports

show.go

@@ -107,7 +107,7 @@ func hasYAMLDirective(native []byte) bool {
 	lines := bytes.Split(native, []byte("\n"))
 	for _, line := range lines {
 		trimmed := bytes.TrimSpace(line)
-		if bytes.Equal(trimmed, []byte("---")) || bytes.HasPrefix(trimmed, []byte("--- #")) {
+		if isYAMLDocumentStart(string(trimmed)) {
 			return false
 		}
 		if bytes.HasPrefix(trimmed, []byte("%YAML ")) || bytes.HasPrefix(trimmed, []byte("%TAG ")) {
@@ -135,8 +135,17 @@ func frameEffectiveYAML(scope string, native []byte) []byte {
 	hasDirective := false
 	for _, line := range lines {
 		trimmed := strings.TrimSpace(string(line))
-		if trimmed == "---" || strings.HasPrefix(trimmed, "--- #") {
+		if isYAMLDocumentStart(trimmed) {
 			out := make([]byte, 0, len(native)+len(comment))
+			// Inline content may be a block scalar; place the label before
+			// its marker rather than interrupting the native value.
+			content := strings.TrimSpace(strings.TrimPrefix(trimmed, "---"))
+			if content != "" && !strings.HasPrefix(content, "#") {
+				out = append(out, native[:position]...)
+				out = append(out, comment...)
+				out = append(out, native[position:]...)
+				return out
+			}
 			out = append(out, native[:position+len(line)]...)
 			if len(line) > 0 && line[len(line)-1] != '\n' {
 				out = append(out, '\n')
@@ -175,3 +184,7 @@ func showFailure(cause error, diagnostics []Diagnostic, reportStarted bool) Outc
 	outcome.ReportIncomplete = reportStarted
 	return outcome
 }
+
+func isYAMLDocumentStart(line string) bool {
+	return strings.HasPrefix(line, "---") && (len(line) == 3 || line[3] == ' ' || line[3] == '\t')
+}